Question: 8 phenotypes were observed as a result of a trihybrid cross. The frequencies of the phenotypes are a+ b+ c- = 570 a- b- c+ = 545 a+ b- c+ = 17 a- b+ c- = 20 a+ b- c- = 140 a- b+ c+ = 128 a+ b+ c+ = 65 a- b- c- = 61 No other information is given. It is not even specified if it is a testcross. How to know if the genes were linked? Also, what are the possible genotypes of the parents? My attempt - The phenotypes with the two largest frequencies represent parental classes. Thus a+ b+ c- and a- b- c+ are parental recombinant phenotypes. The phenotypes a+ b- c+ and a- b+ c- are double recombinant phenotypes as these have the smallest frequencies. The other 4 are single recombinant phenotypes. But I do not know how to proceed from here. Suppose I calculate the % of all the recombinant (single and double) phenotypes and find it to be less than 50%, can I conclude that the genes were linked?